A venous pump mechanism is known in the region of the hand essentially including the proximal phalanges of the digits and thumb and the adjacent regions of the palm and dorsum; this mechanism is naturally brought into operation upon a tight doubling of the fist whereupon venous return flow ensues from the entire arm.
It has been established that by periodically squeezing this region without requiring a patient to double his fist, i.e., by external application of squeezing essentially local to this region, venous return flow may be efficiently stimulated even in the case of a degree of venous obstruction in the wrist or elsewhere in the involved arm.
Additionally, it has been established that such externally applied squeezing pressure can also be accompanied by an improvement in arterial flow in the involved arm.
In European Patent No. 0 228 768 there is disclosed an inflatable mitt for engaging the promimal phalanxes of the fingers and thumb of the hand and adjacent regions such that upon periodic pressurization, localized application of a squeezing force may be applied to those parts to stimulate venous flow.
In related European patent application No. 89305062.5 there is disclosed a circumferentially tying inflatable bag shaped for radially inward active engagement solely with a human hand which may be cyclically inflated, the squeezing pressure then being held for a short time to stimulate arterial flow.
A further similar medical appliance is disclosed in "The Return of Blood to the Heart" (Second Edition) by Gardner and Fox (Published by John Libbey), on page 130, FIG. 69 depicts a pneumatically compressible mitten, the mitten body being formed of slitted Neoprene and enclosing an inflation pad wherein Velcro straps are provided externally to direct the force of inflation towards the hand.
All these medical appliances suffer the disadvantage that although an efficacious increase in venous or arterial blood flow is achieved, all require that a glove or mitten-like structure be worn over the affected hand.
In cases to be treated by medical appliances of these types, the affected hand is likely to be painfully swollen and considerably less mobile than usual.
It is, therefore, clear, that where the fingers of the hand must be maneuvered through particular finger holes in a glove, or where the hand must be maneuvered through the appropriate holes in a mitten, the fitting process is likely to be both time consuming from the point of view of the medical practitioner and painful from the point of view of the patient, and may in some cases be impossible.
A further necessity, of course, will be the requirement that a wide range of sizes of such medical appliances be kept to fit the range of sizes of hand encountered, both in terms of normal variation and degree of swelling.